Boiler Upgrade Scheme grant explained

The Boiler Upgrade Scheme, usually shortened to BUS, is the main England and Wales grant for replacing a fossil-fuel heating system with a heat pump or eligible biomass boiler. It is not a discount code you claim yourself. Your installer applies for it, deducts the grant from the quote and is paid through the scheme after the installation.

The practical points are:

GOV.UK lists one grant per property: £7,500 for air source heat pumps, £7,500 for ground or water source heat pumps, £5,000 for eligible biomass boilers and £2,500 for air-to-air heat pumps.
The installer must be MCS certified and the grant is installer-led. The value should be taken off the quote and invoice rather than paid to you afterwards.
Ofgem says version 5 applies to applications properly made on or after 28 April 2026. The application is not properly made until Ofgem has the required information and the property owner has provided consent and identity verification.
Ofgem says property owners must confirm consent within 14 days of the email request. If confirmation is not received within 14 days, the application may be rejected; the assisted digital route allows longer.
GOV.UK says the installer must commission and install the heat pump within 120 days of applying for the grant. Ofgem’s guidance also warns that retrospective applications carry extra risk because an installation is not guaranteed to be eligible until the application is accepted.
GOV.UK and Ofgem now list £9,000 support for eligible off-gas-grid oil or LPG homes from 21 July 2026 to 31 March 2027. Ask the installer which grant category is being used, whether the property is off the gas grid and whether the voucher application date affects the amount.
Octopus says it applies the grant to eligible heat-pump quotes and handles the paperwork, but the survey can still find extra work or planning steps before installation.

The short version

For most Octopus readers, BUS matters because it can remove a large part of the upfront cost of a heat pump. It does not make every home suitable, and it does not guarantee cheap running costs on its own. The best decision is still a three-part check: whether the house is technically suitable, whether the quote is sensible after the grant and whether the running tariff fits how you heat the home.

If you are considering an Octopus heat pump, the grant can be used through Octopus Energy Services where the property and installation qualify. Octopus says it applies the £7,500 grant to eligible quotes and handles the paperwork, including helping arrange an EPC if needed. Keep the quote and survey notes, because extra planning, asbestos, electrical, cylinder, radiator or building work can change the final price.

Current grant amounts

At the time of writing, the standard BUS grants are:

£7,500 towards an air source heat pump, usually an air-to-water heat pump
£7,500 towards a ground source or water source heat pump
£5,000 towards a biomass boiler, only in eligible rural off-gas-grid properties
£2,500 towards an air-to-air heat pump for residential properties

The government has confirmed temporary £9,000 support for eligible off-gas-grid homes replacing oil or LPG heating with an air-to-water or ground source heat pump. GOV.UK and Ofgem list the higher grant as running from 21 July 2026 to 31 March 2027. Treat that as an installer and voucher-category check rather than a blanket heat-pump discount, because gas-heated homes, air-to-air heat pumps and other off-gas-grid replacement categories can still use different grant values.

BUS is not available for a hybrid heat pump system, and it cannot be used to replace an existing low-carbon heating system.

Who can usually qualify?

The scheme is for property owners in England and Wales. That includes owner-occupiers, second homes, business properties and homes rented out to tenants, as long as the installation meets the rules.

You normally need to be replacing an existing fossil-fuel or electric heating system, such as gas, oil, LPG, storage heaters or panel heaters. The installation must be carried out by an MCS-certified installer, and the installer must apply through the BUS process.

You are not automatically excluded just because you have had separate funding for insulation, windows or other energy-efficiency work. You can be excluded if the property has already received government support for a heat pump or biomass boiler.

Property checks that matter

The old rule that forced you to complete certain loft or cavity wall insulation recommendations before claiming BUS has been removed. That does not mean insulation no longer matters. A poorly insulated home can still need a larger heat pump, higher flow temperatures and higher running costs.

GOV.UK still points households towards a suitable installer for property checks. In practice, the useful questions are:

Does the heat pump have enough outdoor space, airflow and sensible siting?
Will the existing radiators and pipework work well at lower flow temperatures, or are upgrades needed?
Is there room for a hot-water cylinder if the home does not already have one?
Is the EPC valid, missing or out of date?
Does the quote include all plumbing, controls, cylinder work, radiator changes, electrical work and any extra building work discovered at survey?

For Octopus specifically, compare the lower-installation-cost route with the lower-running-cost route if you are offered different system designs. Octopus’s own help material explains that a higher-temperature installation can be cheaper to fit but more expensive to run, while a lower-temperature setup may need more radiator work upfront.

How the application works

You do not usually apply directly. The process is installer-led:

Contact suitable MCS-certified installers and get quotes.
The installer checks whether the property and proposed system are eligible.
You agree the quote with the grant deducted from the amount you pay.
The installer applies to Ofgem for the voucher.
Ofgem contacts you to confirm that the installer is acting on your behalf. Reply promptly, because Ofgem says missing consent within 14 calendar days can lead to rejection.
The installer completes and commissions the installation within the scheme timescales.
The installer redeems the voucher and receives the grant payment.

The important consumer point is simple: the grant should be visible on the quote and invoice. If the grant is not clearly deducted, if Ofgem emails you to confirm consent or identity, or if the quote assumes the £9,000 oil and LPG uplift without showing the right off-gas-grid category and voucher timing, pause and ask before paying a deposit.

What can still trip people up

Most BUS problems are not about the headline grant amount. They come from edge cases around the property, the old heating system or the installer paperwork.

Common checks include:

Existing heating: BUS is for moving away from fossil-fuel or eligible electric heating, not replacing a heat pump you already have.
New builds: most new-build properties are excluded, although self-builds and some completed homes with fossil-fuel heating can be different.
Social housing: GOV.UK lists social housing as excluded from BUS.
Biomass boilers: these have narrower rules than heat pumps and are mainly for rural off-gas-grid properties.
Capacity and standards: the system must meet scheme standards and capacity limits.
Installer quality: the installer needs current MCS certification for the technology being installed.
Voucher timing: most BUS vouchers need the work completed within the scheme deadline. A quote that depends on a future uplift should spell out what happens if the timing changes.
Post-installation checks: MCS says it may carry out routine verification after the grant is claimed. Keep the MCS certificate, quote, invoice and payment evidence so any audit is easy to answer.

If any of these are uncertain, get the answer in writing before relying on the grant.

Scotland and Northern Ireland

BUS covers England and Wales only. Scotland uses the Home Energy Scotland Grant and Loan instead. At the time of writing, that can offer up to £7,500 grant funding for eligible heat pumps, with an optional interest-free loan of up to £7,500 and a rural or island uplift where the property qualifies.

Scottish support has different rules. Home Energy Scotland says funding must be offered in writing before work starts, heat pumps must provide all heating and hot-water requirements and hybrid heat pumps are not eligible.

Northern Ireland does not use BUS either. Check local energy-saving grant guidance before assuming the England and Wales rules apply.

How this links to Octopus and Cosy

The grant reduces the upfront cost. A tariff such as Cosy Octopus affects the running cost. They are related decisions, but not the same decision.

A heat pump can be a good fit with Octopus if the home suits low-temperature heating, the installation quote is clear and you can shift enough heating or hot-water use into cheaper periods. It may be less compelling if the house needs major fabric work first, the quote hides important upgrades, or the household cannot realistically use Cosy’s cheaper windows.

Read heat pumps and Octopus for the wider fit check, then use running costs on Cosy once you are comparing tariffs rather than grants.

If you decide Octopus is still the right supplier after those checks, you can use the referral page before starting the switch.